Despite the victory, Sanders remains far behind Clinton, whose delegate lead is nearly three times the largest lead then-senator Barack Obama ever held over Clinton in 2008.

Sanders will take roughly half of Indiana's 83 delegates, which are awarded proportionally based on each candidate's percentage of the vote, per Democratic Party rules. At the time of publication, Sanders led Clinton 53.2 percent to 46.8 percent, with 68 percent reporting.

With Clinton and Sanders on track to roughly split Indiana's delegates, Clinton will have approximately 1,687 pledged delegates to Sanders's 1,359 pledged delegates. Including superdelegates—party officials who may switch their allegiance—Clinton will have around 2,207 total delegates, giving her nearly 93 percent of the 2,383 delegates needed to secure the Democratic nomination.

Sanders must win 82.5 percent of all available delegates, including the 83 from Indiana, to win the party's nomination, effectively pushing the nomination out of reach. It is technically possible for Sanders to woo Clinton’s superdelegates over to his side, though that is unlikely if he fails to secure the majority of pledged delegates.